Light source having light emitting diode

ABSTRACT

An LED includes an LED chip, a first package configured for packaging the LED chip, the first package including a flat first surface, and a second package including a second surface opposing the first surface. A micro-structure is defined in the second surface and protruding toward the first surface. A gap is maintained between the first and second surfaces. The gap is filled with a filler, and the refractive index of the filler is smaller than that of the first and second packages. Light generated by the LED chip radiates first through the first package, then the gap and the micro-structure, thereafter the second package to finally reach an outside of the LED. A light module including the LED is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of a commonly-assignedapplication entitled “LIGHT EMITTING DIODE AND LIGHT MODULE HAVINGSAME,” filed on Sep. 29, 2010 with application Ser. No. 12/894,122. Thedisclosure of the above-identified application is incorporated herein byreference.

BACKGROUND

1. Technical Field

The present disclosure relates to light emitting diodes (LEDs), and to alight source having the LEDs.

2. Description of Related Art

The maximum radiation angle of an LED is not 180°, so a number of LEDsaligned in a line to emit light yield a number of shadows correspondingto the gaps between adjacent LEDs. These shadows ruin the uniformity ofthe light field produced by the number of LEDs.

Therefore, what is needed is a light source having an LED, which canovercome the above shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present light source having an LED can be betterunderstood with reference to the following drawings. The components inthe drawings are not necessarily drawn to scale, the emphasis insteadbeing placed upon clearly illustrating the principles of the presentlight source. Moreover, in the drawings, like reference numeralsdesignate corresponding parts throughout the views.

FIG. 1 is a cross-sectional view of an LED in accordance with a firstexemplary embodiment.

FIG. 2 is a cross-sectional view of the LED of FIG. 1, taken along lineII-II, showing a micro-structure defined in a second surface of a secondpackage of the LED.

FIG. 3 is similar to FIG. 1, but showing an alternative embodiment ofthe micro-structure of the LED.

FIG. 4 is similar to FIG. 3, but showing an alternative embodiment of alocation of the micro-structure of the alternative embodiment.

FIG. 5 is similar to FIG. 2, but shows the micro-structure of thealternative embodiment.

FIG. 6 is a cross-sectional view of an LED in accordance with a secondexemplary embodiment.

FIG. 7 is a light source incorporating a plurality of LEDs each beingformed in accordance with the first embodiment of FIG. 1 or the secondembodiment of FIG. 6.

FIG. 8 is a cross-sectional view of an LED in accordance with a thirdexemplary embodiment.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an LED 10 in accordance with a firstembodiment includes an LED chip 12, a first package 14, and a secondpackage 18. The first package 14 is configured to encapsulate the LEDchip 12. The first package 14 includes a flat first surface 140. Thefirst surface 140 is the light emitting surface of the LED chip 12.Light beams emitted by the LED chip 12 pass through the first package14. The second package 18 packages the first package 14. The LED chip 12is located on a support surface 160. Conductive wires 120 coupled to theLED chip 12 are electrically connected with lead frames 121.

The second package 18 includes a substantially planar second surface 180substantially parallel to the first surface 140. A micro-structure 20 isformed at the second surface 180 and protrudes from the second surface180 toward the first surface 140. A gap 21 is maintained between thefirst and second surfaces 140 and 180. The gap 21 can be a vacuum or canbe filled with filler 22. The refractive index of the filler 22 issmaller than that of the first and second packages 14 and 18. The filler22, in this embodiment, is air. The filler 22 may instead be another gasor liquid.

The micro-structure 20 includes a number of V-shaped protrusions 200(see FIG. 2) parallel to each other. The V-shaped portions 200 each havea pointed end (not labeled) in the shape of a line. The V-shapedprotrusions 200 are connected to each other without gaps between them,or there is a predetermined distance between each two adjacent V-shapedprotrusions 200. Each pointed end is near the first surface 140 butstill spaced from the first surface 140, as shown in FIG. 1.Alternatively, each pointed end can be in contact with the first surface140 (see FIG. 6, described below). The micro-structure 20 may insteadconsist of a number of cones 202 (see FIGS. 3-5) or other protrusions.The cones 202 are uniformly distributed on the second surface 180. Thecones 202 may connect to each other; or may be separated from each otheras shown in FIGS. 3-5. The cones 202 each have a peak 204. Each peak 204is near the first surface 140 (FIG. 3), or is in contact with the firstsurface 140 (FIG. 4).

The first package 14 may be any one of a number of transparentmaterials, such as epoxy resin, silicone resin, or glass. The secondpackage 18 may be any one of a number of transparent materials, such asepoxy resin, silicone resin, or glass. The first package 14 includesphosphors 142 configured to change the color of light beams into adifferent color.

The micro-structure 20 is not in contact with the first surface 140, oronly the pointed ends of the micro-structure 20 are in contact with thefirst surface 140. The light beams of this embodiment first enter anoptically thinner medium (the air 22 in the gap 21) from an opticallydenser medium (the first package 14), and then enter another opticallydenser medium (the second package 18), so that the radiation angle ofthe light beams in such other optically denser medium (the secondpackage 18) is larger. Furthermore, the micro-structure 20 allows thelight beams to enter the first package 18 at a bigger refraction angle.

Referring to FIG. 6, an LED 30 provided by a second embodiment issimilar to the LED 10 of the first embodiment. The main differencebetween the LED 30 and the LED 10 is that a bottom end of themicro-structure 31 contacts the first surface 34. The micro-structure 31is formed at the second surface 380 and protrudes from the secondsurface 380 toward the first surface 34. A gap 33 is maintained betweenthe second surface 380 and the first surface 34. The gap 33 also existsbetween each two adjacent V-shaped protrusions of the micro-structure31.

Referring to FIG. 7, a light module 50 in accordance with the presentdisclosure is shown. The light module 50 includes a light guide plate52. A light incident surface 520 is defined in one side of the lightguide plate 52. A number of the LEDs 10 is arranged adjacent to thelight incident surface 520. The LEDs 10 are aligned along a linesubstantially parallel to the light incident surface 520. The LEDs 10have larger radiation angles. The light module 50 therefore has a moreuniform optical field with smaller or no shadow areas. The lightincident surface 520 is a flat surface, and may be distributed withmicro-structures to raise the uniformity of the optical field. The LEDs10 can be replaced by the LEDs 30.

Referring to FIG. 8, an LED 60 of a third embodiment is provided. TheLED 60 is similar to the LED 10 of the first embodiment. The maindifference between the LED 60 and the LED 10 is that the outer surface600 of the LED 60 is a flat surface, whereas the LED 10 has a curvedouter surface. The LED 60 is more compact, whereas the LED 10 has alarger radiating range.

The LED 60 includes an LED chip 61, a first package 62, and a secondpackage 63. The first package 62 is configured to package the LED chip61. The first package 62 has a flat first surface 620. The secondpackage 63 has a planar second surface 630 substantially parallel to thefirst surface 620. A micro-structure 631 is formed at the second surface630 and protrudes from the second surface 630 toward the first surface620. A gap 64 is maintained between the first surface 620 and the secondsurface 630. A refractive index of a filler 640 filling in the gap 64 issmaller than that of the first package 62 and the second package 63. Thefiller 640 may be any one of a number of materials such as, air, water,another gas, or another liquid. The filler 640 is air in thisembodiment.

The second package 63 is located over the first surface 620, andcontacts the first surface 620 with a bottom end of the micro-structure631 touching the first surface 620. The second package 63 may alsocompletely encapsulate the first package 62. The second package 63 is aflat plate. The second package 63 is made of epoxy resin.

Traditionally, the light beams directly enter the second package 63 fromthe first package 62; in this embodiment the light beams first enter anoptically thinner medium (the air in the gap 64) from an opticallydenser medium (the first package 62), and then enter another opticallydenser medium (the second package 63), the radiation angle is larger.Furthermore, the micro-structure 631 allows the light beams to enter thesecond package 63 at a larger refraction angle.

The LEDs provided by the embodiments may package only one LED chipinside or more than one.

It is understood that the above-described embodiments are intended toillustrate rather than limit the disclosure. Variations may be made tothe embodiments without departing from the spirit of the disclosure.Accordingly, it is appropriate that the appended claims be construedbroadly and in a manner consistent with the scope of the disclosure.

What is claimed is:
 1. A light source, comprising: a light guiding platecomprising a light incident surface; and a plurality of LEDs arrangedadjacent to the light incident surface, each LED comprising: an LEDchip; a first package configured for packaging the LED chip, the firstpackage comprising a flat first surface; and a second package configuredfor packaging the first package, the second package comprising a planarsecond surface substantially parallel to the first surface, and an outersurface, wherein a micro-structure is formed at the second surface andprotrudes from the second surface toward the first surface, a gap ismaintained between the first and second surfaces, the gap is filled witha filler, and a refractive index of the filler is smaller than that ofthe first and second packages; light generated by the LED chippenetrating the first surface of the first package, then entering thefilled gap, and then passing through the micro-structure and the secondsurface to enter the second package, and finally exiting from the outersurface of the second package.
 2. The light source of claim 1, whereinthe plurality of LEDs are arranged in a line substantially parallel tothe light incident surface.
 3. The light source of claim 1, wherein themicro-structure comprises a plurality of V-shaped protrusions parallelto each other, each of the plurality of V-shaped protrusions comprises astraight sharp ridge, and the ridge is in contact with the firstsurface.
 4. The light source of claim 1, wherein the micro-structurecomprises a plurality of V-shaped protrusions parallel to each other,each of the plurality of V-shaped protrusions comprises a straight sharpridge, and the is adjacent to and spaced apart from the first surface.5. The light source of claim 1, wherein the micro-structure comprises aplurality of cones, each of the plurality of cones comprises a peak, andthe peak is in contact with the first surface.
 6. The light source ofclaim 1, wherein the micro-structure comprises a plurality of cones,each of the plurality of cones comprises a peak, and the peak is nearand spaced apart from the first surface.
 7. The light source of claim 1,wherein the first package is embedded in the second package, the outersurface of the second package is a curved surface, and the secondsurface is positioned between the first surface and the outer surface.8. The light source of claim 1, wherein the second package lies on thefirst package, the outer surface of the second package is a flatsurface, and the second surface is positioned between the first surfaceand the outer surface.
 9. The light source of claim 1, wherein thefiller is the air.
 10. The light source of claim 1, further comprisingphosphors scattered in the first package to change the color of thelight beams into a different color.